Dual tank sonic processing system and method



DUAL TANK SONIC PROCESSING SYSTEM AND METHOD Filed June 23, 1967 F. MASSA July 14, 1970 2 Sheets-Sheet 1 INVENTOR FHA /VK MA 554 United States Patent Oflice 3,520,724 DUAL TANK SONIC PROCESSING SYSTEM AND METHOD Frank Massa, Cohasset, Mass, assignor to Massa Division, Dynamics Corporation of America, Hingham, Mass.

Filed June 23, 1967, Ser. No. 648,444 Int. Cl. 1306b 1/06, 3/04; B08b 7/02 U.S. Cl. 1341 15 Claims ABSTRACT OF THE DISCLOSURE This invention relates to sonic processing systems and more particularly to sonic systems requiring very high power output and using very large tanks.

Sonic processing systems generally include tanks of liquids having electroacoustical transducers therein for imparting high frequency sonic vibrations to the liquid. For example, if small parts are put into the liquid and then the transducers are operated, the liquid vibrates to create intense pressure waves which wash across the surfaces of the parts, and clean them. Those skilled in the art will readily perceive many other uses for sonic processing systems including the acceleration of chemical reactions and the formulation of fine emulsions of incompatible liquids.

The usual sonic processing systems have relatively small tanks holding relatively small amounts of liquid. However, there are needs for systems utilizing large tanks that may range in size from, say, five feet in diameter by five feet tall to ten feet in diameter by thirty feet tall. For tanks of these large dimensions, the power demanded from the transducer becomes very large. For example, the transducers in a tank of this size may be required to generate sonic power in the range of hundreds of kilowatts to a megawatt. These power levels are much greater than the sonic processing power levels used heretofore.

Accordingly, an object of this invention is to provide new and improved very large size sonic processing systems. In this connection, an object is to provide such systems from readily available component parts which have already been developed and are commonly used in smaller systems. Here, an object is to provide a sonic system utilizing an array of relatively small, low cost components to generate large amounts of sonic power inside of a large tank containing a liquid.

Another object is to provide a pressurized and temperature controlled sonic processing system capable of sonically treating materials under the most exacting environmental conditions which, nevertheless, may be operated with ease and convenience similar to that found in an open vat system.

Yet another object of this invention is to accomplish the above objects and fulfill the above stated needs by equipment having a design which allows further development and enlargement, even after the equipment is in place and operating. Here, an object is to accomplish this further development and enlargement at a minimum cost and without making the old and pre-existing equipment obsolete or the new equipment a design comprise.

3,520,724 Patented July 14, 1970 In keeping with an aspect of the invention, these and other objects are accomplished by providing a dual tank arrangement. In a preferred embodiment, a first tank is a large permanent container having a basket-like liner therein which can be removed and replaced as required. The basket-like liner is arranged to receive and support a number of relatively small transducer modules which may be of a type which is in common use. When the liner is in place, the transducers effectively line the entire inner wall of the first tank. Each small transducer mounted in the basketlike structure is focused upon the axis of the large tank to create an intensely concentrated sound field in the coupling liquid which is contained in the tank. All transducers are arranged for operating while submerged below the surface of the coupling liquid.

A second and smaller tank is arranged to be lowered into the first tank and completely immersed under the surface of the coupling liquid. This second tank may contain the material to be processed by the sonic system. The wall of the second tank is transparent to the sonic energy which impinges upon its surface. This is the energy transmitted from the submerged transducers through the coupling liquid to the smaller tank.

One advantage of this arrangement is that the coupling liquid in the first tank may be any which is most ideally suited to operation with the transducers. The second tank contains the material to be processed which is completely independent of the coupling liquid. The second tank also serves to isolate the processed material from the transducers. This isolation means that the transducers do not have to have a special design. Among other reasons, this is because the transducers are not immersed in the processing fluid and, therefore, not exposed to the hostileto transducersenvironments of the temperature and pressure required in the processing chamber.

Another advantage of the invention is that the smaller tank may be filled or emptied quickly and easily outside the sonic system and may be pressurized or heated for a desired operation.

The nature of the invention, together with the operation thereof may be understood best from a study of the attached drawings, in Which:

FIG. 1 is a perspective view of a dual tank sonic processing system of a type which incorporates the principles of the invention;

FIG. 2 is a cross-sectional view of the first tank shown in FIG. 1 and taken along line 2-2 thereof;

FIG. 3 is a cross-sectional view of the first tank taken along line 33 of FIGS. 1 and 2; and

FIG. 4 shows an alternative embodiment wherein the smaller of the two tanks is replaced by an immersed coil, and the material to be processed is pumped through the coil.

According to a preferred embodiment of the invention, a novel sonic processing system for generating and utilizing sonic energy includes a first tank 50 containing a plurality of transducers submerged in a coupling liquid and a second tank 51 containing the material which is to be processed. Each tank is, in effect, an independent universe which may be designated to operate in its most efiicient manner independently of the other.

The tank 50 is filled to a level 52 by a coupling liquid selected to have the most ideal sound transmitting characteristics for any particular system needs. Usually, the coupling medium is water or oil which has been degassed to permit the transmission of high sound pressure levels without cavitation.

The tank 51 is made from a sound transparent material, such as steel, with a wall thickness which permits the passage of sound with negligible attenuation. The thickness of the wall can be increased as the frequency is decreased. For example, the small tank may have steel walls up to a quarter-inch thick if the sonic frequency is in the region of 5000 c.p.s. The specification of this wall material is made on a basis of its compatibility with the contents of the tank 51 and the process followed when the sonic system is used. The compatibility problems might be related to either the corrosive nature of the fluids or the physical working conditions required inside the tank 51.

The tank 51 may be made to be opened and closed quickly and easily, as by providing a cover 55 which may be attached and sealed to a main chamber 56 by means of a camming dog or a bolt and wing nut arrangement 57. A valve mechanism 58 permits the tank to be pressurized, or, the tank may be coupled to an external pump and filter arrangement, as required, by the particular process that is being used. Also, heating or cooling equipment may be included in the tank 51. A lift ring 59 is arranged so that a cable 60 may be attached thereto. Thus, the second tank 51 may be packed or unpacked at any convenient point and then hoisted into or lifted out of the tank 50 by any convenient means.

The tank 50 is here shown as having a cylindrical shape; although, other suitable shapes may also be provided. A somewhat basket-like frame 65 is designed to fit loosely inside the tank 50, and serve as a liner thereto. FIG. 2 shows that this liner 65 has a cross-sectional shape and size which is approximately the same as those of the tank 50. FIG. 3 shows that the height of the basket 65 is also shaped to match the shape of the tank 50, but the total height of the liner is somewhat less than the height of the tank 50. This way, the entire basket-like liner 65 is submerged under the surface 52 of the coupling liquid 66 when the tank 50 is filled.

The basket-like arrangement 65 is adapted to receive and support an array of transducer elements, one of which is numbered 67 in each of the figures. All of these transducers are focused on the axis of the cylinder, as indicated by the lines a, b, c, etc. in FIG. 2. While any suitable and well known transducer may be used, an exemplary structure might use the transducer disclosed in US. Pat. No. 3,199,071. If the basket 65 is approximately five feet tall and five feet in diameter, there might be as many as a few hundred transducers mounted on frame 65 and arranged to line the inner wall of the tank 50.

Any suitable means may be provided for conveying the necessary A.C. electrical signals to drive the transducers. For example, any well known waterproof cables may be connected between the power source and the transducers.

The operation of the system should now be apparent. The basket-like liner 65 is placed in the tank 50. Then the coupling liquid is added to a level which completely covers all transducers. The tank 51 is filled with the material to be processed and the desired physical environment of pressure and temperature is established. Thereafter, the tank 51 is lowered into tank 50 at a desired location relative to the sound field produced by the transducers. Power is applied to the transducers, and a concentrated sound field is set up which is directed toward the center of the tank. The generated sound energy is propagated through the coupling liquid which fills the tank 50 and transmitted through the walls of the tank 51, thereby causing an intense sonic activation of its contents.

The foregoing description covers a preferred embodiment of the invention wherein a coupling liquid in a stationary tank is driven by an array of transducers, and the material to be sonically treated is agitated in a separate tank which is suspended in the stationary tank.

A modification of the invention is shown in FIG. 4 Where a long length of coiled tubing 70 replaces the processing chamber 51. The coil 70 is suspended into the tank 50, and coupled to means for pumping the material to be processed through the coil. The pumping means is symbolically indicated by the arrows 71, 72. While the material is so circulating inside the coil, it is exposed to the sonic field established in the coupling liquid 66 by the transducers. The sonic energy is transmitted through the walls of the coil to the material inside the coil.

According to yet another embodiment of the invention, the material to be processed may be placed within individual packages. Then, the packages may be put into a second container such as 51 and lowered into the tank 50 for processing. Since the walls of the packages may form the walls of the processing chamber, the tank 51 may be made as either as open wire-like or a solid wall container. When a wire-like container is used, the packages are submerged directly in the coupling liquid 66 contained within the tank 50. When the packages are placed inside a solid wall container 51, a second coupling liquid will be required to fill the tank 51 in order to complete the acoustic coupling between the transducers to the individual packages. When packages are placed within a solid wall container, including a second coupling liquid the individual packages being processed may then be subjected to any heat cycle or pressurization desired during the sonic processing cycle.

Briefly in rsum, I have solved the problem of providing very high sonic power in large tank. In order to process material by sonic activation in such large tank, I employ a dual tank system. The inside surface of the wall of a first large open tank is effectively lined with an array of separate individual transducers, allarranged to direct their sonic energy toward the center of the tank. The material to be processed is placed inside a second tank which is smaller than the first tank. The second tank is then placed inside the first tank, and submerged under a coupling liquid such as water or degassed oil. This liquid completely fills the space between the transducers and the center walls of the second tank and serves to conduct the sonic energy generated by the transducers to the second tank. This way, the second tank may be pressurized or heated independently of the liquid in the first tank. The dual tank system permits the use of a large number of low cost transducers to generate large amounts of sonic power at a low cost. The system also provides an almost unlimited choice of tank sizes and power densities by simply using more or less transducers in any desired configuration.

Those skilled in the art will readily perceive still other embodiments of the invention. Therefore, the appended claims are not to be construed as necessarily limited to the disclosed structure. Quite the contrary, the claims are to be construed broadly enough to cover all equivalents reasonably falling within the true scope of the invention.

I claim:

1. A method for sonic processing including the steps of (1) generating a converging cylindrical sound field within a tank containing a liquid, (2) placing a material to be sonically processed within at least one separate container, (3) immersing said separate container within the liquid contained in said tank, and (4) independently establishing a temperature environment within said separate container, said separate container being imperforate and adapted to be removed from said tank after said material is sonically processed.

2. A method for sonic processing including the steps of (1) generating a converging cylindrical sound field within a tank containing a liquid, (2) placing a material to be sonically processed within at least one separate container, (3) immersing said separate container within the liquid contained in said tank, and (4) independently establishing a pressure environment within said separate container, said separate container being imperforate and adapted to be removed from said tank after said material is sonically processed.

3. The method of claim 2 and (5) forcing the material through said separate container.

4. A method for sonic processing including the steps of (l) generating a converging cylindrical sound field within a large industrial processing tank containing a liquid, said sound field being in the low audible range, (2) placing a material to be sonically processed within at least one separate container, said container having a solid metal wall at least inch thick, (3) lowering and immersing said separate container within the liquid contained in said tank, (4) positively and independently pressurizing said container, and (5) raising said container out of said tank.

5. A sonic processing system comprising a first tank lined with a plurality of transducer elements, a coupling liquid substantially filling said first tank and completely covering said transducer elements, a second tank immersed in said coupling liquid and containing material to be sonically activated, the walls of said second tank being transparent to the sonic energy generated by said transducer elements and impervious to both said coupling liquid and the contents of said second tank, and means for holding the temperature of the sonically activated material at substantially a predetermined degree by accurately controlling the temperature of the liquid in at least one of said tanks.

6. The system of claim 5 wherein said second tank comprises a coil of tubing, said material to be activated being pumped through said coil while it is immersed in said coupling liquid and said transducer elements are generating said sonic energy.

7. The invention in claim 5 characterized in that said first tank is generally cylindrical in shape and further characterized in that said second tank is also cylindrical in shape.

8. The invention of claim 5 wherein said second tank comprises a coil of tubing, and means for pumping a material to be sonically activated through said coil under a positive and fixed pressure.

9. A sonic processing system comprising a first tank lined with a plurality of transducer elements, a coupling liquid substantially filling said first tank and completely covering said transducer elements, and a second tank immersed in said coupling liquid and containing material to be sonically activated, the walls of said second tank being transparent to the sonic energy generated by said transducer elements and impervious to both said coupling liquid and the contents of said second tank, wherein said second tank is adapted to be successively raised from and lowered into said first tank to process said material, and means for pressurizing said second tank independently of any pressure in said first tank.

10. A sonic processing system comprising a first tank lined with a plurality of transducer elements, a coupling liquid substantially filling said first tank and completely covering said transducer elements, a second tank immersed in said coupling liquid and containing material to be sonically activated, the walls of said second tank being transparent to the sonic energy generated by said transducer elements and impervious to both said coupling liquid and the contents of said tank, said second tank being adapted to be successively raised from and lowered into the first tank to sonically process said material, and means for separately and positively elevating the pressure in one of said tanks.

11. An industrial sonic processing system comprising a large tank having a length and width, each greater than three linear feet, means comprising an array of transducers mounted in proximity to the inner wall of said large tank, means suspended in said tank comprising a movable second and inner container having a solid closed waterproof wall at least inch thick, a coupling medium in said tank and filling the space between the walls of said tank and said container, and hydrostatic pressure control means inside said inner container for maintaining substantially a constant and positive pressure level.

12. The system of claim 11 and temperature control means inside said inner container.

13. The system of claim 11 wherein said inner container comprises a helical conduit having a total length exceeding ten feet submerged in said tank.

14. The system of claim 13 and temperature control means in said conduit.

15. A large scale, high power, industrial sonic processing system including a cylindrical tank having a height and diameter, each of these dimensions being greater than five linear feet, sonic energy generating means comprising an array equal to or more than one hundred high power sonic energy transducers operating at frequencies below 25 kHz. lining a loose cylindrical frame positioned inside said tank in the proximity of the inside wall of said tank, said transducers being mounted on said frame to focus sonic energy toward the center line of said cylinder, a second movable solid wall material processing container dimensioned to fit inside said tank, and means for independently pressurizing said container during said sonic processing.

References Cited UNITED STATES PATENTS 1,734,975 11/1929 Loomis et al 99-250 2,407,462 9/ 1946 Whiteley.

2,585,103 2/1952 Fitzgerald.

2,845,077 7/1958 Branson 1341 XR 2,860,646 11/1958 Zucker 1341 XR 2,919,215 12/1959 Neuhaus et a1 1341 2,950,725 8/1960 Jacke et al 134-1 XR 2,985,003 5/1961 Gelfand et al 1341 XR 2,987,068 6/1961 Branson 1341 XR 3,318,578 5/1967 Branson 1341XR MORRIS O. WOLK, Primary Examiner D. G. MILLMAN, Assistant Examiner US. Cl. X.R. 134184; 259-1 

